Irig-B - GE L30 Instruction Manual

3.2 WIRING
IRIG-B is a standard time code format that allows stamping of events to be synchronized among connected devices. The
IRIG-B code allows time accuracies of up to 100 ns. Using the IRIG-B input, the L30 operates an internal oscillator with 1
µs resolution and accuracy. The IRIG time code formats are serial, pulse width-modulated codes that can be either DC
level shifted or amplitude modulated (AM). The GE MultiSync 100 1588 GPS Clock as well as third-party equipment are
available for generating the IRIG-B signal; this equipment can use a global positioning system (GPS) satellite system to
obtain the time reference so that devices at different geographic locations can be synchronized.
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Using an amplitude modulated receiver causes errors up to 1 ms in event time-stamping.
The L30 is intended for use with external clocks that set the IRIG-B control bits according to IEEE Std C37.118.1-
NOTE
2011. When used with a source that sets the IRIG-B control bits according to IEEE Std 1344-1995, the source must
have the sign of its local time offset setting reversed, and if daylight savings time (DST) is used, the source's DST
start and DST stop date settings must be interchanged.
When IRIG-B is used as the time synchronization source for synchrophasors, the DC level shifted option must be
used in order to achieve the 1% Total Vector Error specified by the standard. If amplitude modulated IRIG-B is
used, it results in a 20 to 25 degree error in the synchrophasor angle measurement. The IEEE 1588 Precision Time
NOTE
Protocol can also be used to achieve accurate time synchronization for synchrophasor calculation.
3-30
Figure 3–28: OPTIONS FOR THE IRIG-B CONNECTION
L30 Line Current Differential System
3 HARDWARE

3.2.10 IRIG-B

GE Multilin